Electron tube base



' Dec. 9, 1941. B. A. COFFIN ELECTRON TUBE BAS E Filed Au 2, 1940 a INYENTOR. e4,

CLMQCLLLQ.

Patented Dec. 9, 1941 UNITED STATESATENT OFFICE ELECTRON, TUBE BASE Bruce A. Coffin, Peabody, Mass. Application August 2, 1940, Serial No. 349,759

4 Claims. (Cl. 250--27.5)

This invention relates to an electrical connector, and specifically to a tube base for an electronic tube or similar device.

The invention has for an object to provide a novel and improved tube of the type provided with a metallic shell forming a part of the base and in which provision is made for electrically and mechanically connecting the metallic shell to a ground connection terminal in a simple and efiicient manner, and whose construction is such as to minimize the number of assembly operations whereby the tube may be more economically produced.

Another object of the invention is to provide a novel and improved base for a tube in which the metallic shell portion of the base is provided with an integral ground connection strap and whose construction is such as to facilitate the assembly of the various parts of the tube whereby to efiect a substantial economy in the-cost of production.

A further object of the invention is to provide a novel and improved tube of the character described embodying a central metallic shield memher, and in which provision is made for connecting the shield member together with the metallic shell to a ground connection terminal in a simple, economic and efiicient manner.

In its broader aspects, the invention contemplates a novel electrical connecting unit embodying a metallic shell in which provision is made for groundin in-anoveland improved manner.

With these general objects in View and such others as may hereinafter appear, the invention consists in the electrical connector, in the electronic tube and in the various structures, ar-

rangemcnts and combinations of. parts hereinafter described and particularly defined in the claims at the end of this specification.

In the drawing illustrating thepreferred embodiments of the'invention, Fig.1 is a cross-sectional view of an electronic tube embodying the present invention, the section being taken on the line l-l of Fig.2; Fig. 2 is a plan View in crosssection of the base. portion of the tube shown in Fig.1; Fig.3 is'a view similar to Fig. 2 showmore economically produced. The base portion of the tube preferably includes an insulating disk provided with the usual connection pins including a grounding terminal. The insulating disk is adapted to receive a metallic shell in assembled relation therewith, and in the fabrication of the tube, it is necessary to connect the metallic shell to the ground connection terminal for the purpose of grounding the shell.

In accordance with the present invention, a grounding lug or strap is formed integrally with the metallic shell and is designed so that when assembled with the insulated disk, the strap will extend to the grounding terminal. The strap may then be secured to the top of the grounding terminal or connection pin in any suitable or convenient manner such as by clamping the lug under the head of the terminal pin or by soldering or welding the parts together. This results in the elimination of one of the wires formerly required to be inserted into the hole in the terminal and greatly facilitates the assembly operation.

When the tube is of the type requiring a central shielding member, in the form of a metal cylindrical member, this shield must alsobe electrically connected to the grounding terminal. Prior to the present invention, this connection was made by soldering or otherwise suitably .securing a wire, one end to theshield and the other end to the grounding terminal. In accordance with the present invention, provision is madefor extending the integral grounding lug into contact with the central tubularshield to be soldered or otherwise secured thereto, thuseliminating a second wire which formerly was necessary to be extended into the ground connection pin.

In practice, apreferred form of the invention may comprise a metallic shell stamped out of one sheet of metal to provide an annular portion having a strapconnection horizontally extended from the lower edge of the annular portion to a ground connectiomand a central portion integral with said strap having an opening therein adapted toreceive the central shielding member in press fit or drive fit engagement. Additional strap extensions leading from the lower edge of the annular portion to the central portion serve assupportingmembers whereby to form an integral unit electrically connecting the shell and the central shielding member to a common grounding terminal.

Referring now to the drawing, Fig. 1 repre sents a tube which may comprise abulb 10 containing ,the several elements of a thermionic valve, not shown, and a base portion or insuual terminal pins Id of thetube.

lating disk l2 composed of dielectric material. The insulating disk 12 is provided with the usual contact terminals or pins I4 spaced about a central locating plug or key IS. The base also includes a cylindrical shell portion l8 composed of metal which fits over a ridge portion 20 and on top of a shoulder 22 provided on the disk. The shell 18 is preferably secured to the disk l2 by bending the lower edge of the shell inwardly at selected points 24 into grooved portions 26 provided therefor. The base thus formed provides a cup-shaped receptacle in which the bulb I is secured. r V 7 As illustrated in Figs. 1 and 2, a preferred for of the electrical connecting unit contemplates a unitary grounding connection between the cylinwith an enlarged portion'30 having a hole 32 therein which coincides with the center of one of the terminal pins [4 when assembled with the disk. The strap 28 is extended beyond the terminal and is provided with a second enlarged portion 3| centrally disposed with relationto theAshell l8 and having an opening 33therein 1 adapted to receive the central shielding member 38 in press fit ordrive fit engagement therewith. As shown in Fig. 2, additional strap connections 35, 31 are extended from the lower edge ofthe cylinderto the centrally disposed enlarged portion 3| 'which serve as supporting members, the provision of which'also serves to facilitate the fabrication of the unit in the stamping out process.

i'As shown in Fig. 1, the metal cylindrical shield member 38 is inserted into and extends above the hollow portion within thelocater plug l6 for the purpose of providing an electrostatic and electromagnetic .shield between the individual stem connection leads and between the individ- In the preferred embodimentof the invention,-the central shielding member- 38 is provided with a beaded or shouldered portion 39 which is arranged to seat against theenlargedportion 3! of the shell connection whenasser'nbled therewith. J The lower portion of the shield 38 is preferably tapered larged portion 34 of the pins serves as a shoulder to engage the underside of the disk. In order to secure'the grounding lug 28 to one of the terminal pins 14, theend of the terminal pin selected isextended through a hole in the insulating disk and through the hole 32 in thelug and the extended endis likewise. swaged or bent .over thtbp of th e enlarged porticn as illustrated Although the preferred 'rriethod of connectin g the strap 284and 'the selected terminal .I4 is as above described -it will' be; 'understood that such connection may Joemade infvarious .ways including welding, "soldering orcrimping one to the other.

In practice, a predete ined terminal is selected to -serve as the ground connection and as herein shown. in order to assure proper regis- ,bodied in other forms tration of the strap 28 with the pre-selected pin l4 when assembling, a plurality of grooves or clearance channels 36 are provided in the disk l2 which extend through the ridge portion 20 and into which the strap connections 28, 35, 31 are arranged to fit. Such grooved portions in addition to aligning the grounding lug with the proper terminal also serve to lock the cylindrical shell 3 to the insulating disk to prevent relative rotary movement between the parts. The grooved portions may be extendedslightly be low the shouldered or flanged portion 22, as indicated at 31 in Fig. 4, to present the top of the strap 28 flush with the top of the shouldered portion 22 of the disk so that, when assembling, a standard length of pin I4 may be used.

. Referring now to Fig. 3, where the tube is of the type not provided with a central shielding member, the strap 28 may extend only to the terminal M as illustrated. The strap maybe provided with an enlarged portion 30 having a hole 32 through which the pin I4 is extended and fixed in a manner similar to that as described in connection with Fig. 2. v r

A modified form of the electrical connecting unit including a central shielding member 38 is illustrated in Fig. 5. As therein shown, the connection to the shield 38 is preferably made by extending the grounding strap 28 beyond the terminal point a sufiicient distance to contact the member 38. In its preferred form, the extended strap is bent upwardly as indicatedat 40 and the upright portion is soldered, welded or otherwise secured to the shielding member as by being formed integrally therewith to form a support for the latter and to provide an efficient grounding connection.

From the above description, it will be observed that the novel construction of the tube base of the present invention provides a simple and efficient grounding connection from the metallic portion of the base to the grounding terminal and from the inner shielding member to the same terminal and that, as a result of such construction, the assembling of the base is facilitated and the number of assembly operations is substantially reduced to a minimum.

For some purposes the metallic shell 18 may have fitted in telescoping relation thereon or thereover, an outer metallic shield member indir The present tube base is particularly useful in the manufacture of electron discharge tubes, vacuum tubes, gaseous discharge tubes, thermionic valves, cathode ray tubes, and any other electronic tubes or devices, and in its broader aspects, the invention finds utility as a novel.v

and highly useful electricalconnector.

While the preferred embodiment of the invention has been herein-illustrated and described, it

will be understood that the invention may be emj- H withinthe scope of the followingclaims. I

Having thus described claimed is:.

. .1. A tube base comprising adisc of insulating material having a plurality of connection'pins extending from one face of saidv disc and spaced 7 from the center-of said disc, a cylindricalmetal the invention, whatlis;

thereof, said shell having a plurality of circumferentially spaced metallic straps connected thereto and extending inwardly along said other face of said disc and being joined together adjacent the center of said disc, one of said straps having a portion provided; with an aperture spaced from the center of said disc, one of said pins extending through said aperture and making electrical contact with said last mentioned strap.

2. A tube base comprising a disc of insulating material having a plurality of connection pins extending from one face of said disc and spaced from the center of said disc, a cylindrical metal shell secured to said disc and extending from the other face of said disc adjacent the periphery thereof, said shell having a plurality of circumferentially spaced metallic straps connected thereto and extending inwardly along said other face of said disc and terminating in a central portion common to said straps, said central portion being provided with an aperture, a shield member positioned within said aperture and electrically connected to said shell by said straps, said shield member extending axially from said one face of said disc between said pins for substantially their entire length and from said other face of said disc for a substantial distance within said shell, one of said straps having a portion provided with an aperture spaced from the center of one of said disc, said pins extending through said aperture and making electrical contact with said last mentioned strap.

3. A tube base comprising a disc of insulating material provided with a hollow centrally disposed guide member of insulating material extending axially from one face thereof, a plurality of connecting pins secured in said disc and extending from said one face of said disc said pins surrounding said guide member, said disc being provided with a plurality of inwardly extending grooves in its other face, a cylindrical metal shell secured to said disc and extending from said other face of said disc adjacent the periphery thereof, said shell having a plurality of integral metal straps extending inwardly and positioned in said grooves, said straps terminating in an integral central portion common to said straps and provided with an aperture, a shield member positioned within said aperture and being electrically connected to said central portion, said shield member extending within said hollow guide member between oppositely disposed connection pins for substantially their entire length and extending axially from said other face of said disc for a substantial distance within said shell, one of said straps being provided with a portion having an aperture spaced from the center of said disc, one of said pins extending through said aperture and being electrically connected to said last mentioned strap.

4. A tube base comprising a disc of insulating material having a plurality of connecting pins extending from one face of the disc and spaced from the center of the disc, a cylindrical metal shell secured to said disc and extending from the other face of said disc adjacent the periphery thereof, a metallic strap connected to said shell and extending along said other face of said disc. said strap having an aperture spaced from the center of said disc, one of said pins extending through said aperture and having a head adjacent said other face of said disc making electrical contact with said strap, the portion of said strap surrounding said aperture being positioned between said other face of said disc and the head of said one pin.

BRUCE A. COFFIN. 

